13 research outputs found

    Testing of potential biomarkers of cerebral ischemia and vasospasm in patients with cerebral aneurysm surgery

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    Biomarkers for the prediction of vasospasm and delayed cerebral ischemia in patients with a ruptured cerebral aneurysm could be helpful. In this prospective clinical study, endothelin-1, lactate, pCO2, and pO2 were measured in arterial and internal jugular vein blood before, during and after surgical treatment of a cerebral aneurysm, and were tested as potential predictors of neurologic outcome in patients. Forty-one patients were enrolled in the study, 23 of them were operated on after aneurismal rupture with development of subarachnoid hemorrhage (SAH) and 18 patients were operated on for a nonruptured aneurysm. All of the involved patients survived. There was no difference in neurologic outcome between those operated on with a ruptured or nonruptured aneurysm. Endothelin-1 and lactate concentrations as well as pO2 and pCO2 from arterial and venous blood samples and their venoarterial difference did not differ between groups with and without an aneurismal rupture. Venoarterial difference of endothelin-1 concentrations on the day after surgery significantly differed between the groups with favorable and nonfavorable neurologic outcome. Other variables did not show a statistically significant difference. Significant correlation was found between endothelin-1 and lactate concentrations, suggesting involvement of the same pathophysiological process. Another interesting finding was lower arterial and venous pCO2 in patients with lower initial Glasgow Coma Scale (GCS) score and higher Hunt Hess score in the phase after extubation. We can conclude that the measured biochemical parameters did not show sufficient predictive power to be useful for prediction of cerebral vasospasm and neurologic outcome in everyday clinical practice. However, some correlations that do exist between them suggest involvement of the same pathophysiological process

    Efficient removal of priority, hazardous priority and emerging pollutants with Prunus armeniaca functionalized biochar from aqueous wastes: Experimental optimization and modeling

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    This paper investigates the ability of the phosphoric acid functionalized Prunus armeniaca stones biochar (AsPhA) prepared by thermochemical activation to remove lead (Pb2+), cadmium (Cd2+), nickel (Ni2+), naproxen and chlorophenols from aqueous wastes. The engineered biochar was characterized using the Scanning Electron Microscopy, Energy-dispersive X-ray Spectroscopy, Fourier Transform Infrared Spectroscopy and Brunauer, Emmett and Teller technique. The batch studies were performed by varying the initial pH of the solution (2-9), adsorbent dosage (0.2-10 g L-1), contact time (5-60 min), temperature (22, 32 and 42 degrees C) and initial adsorbate concentration (5-500mg L-1). With the optimal process conditions, the adsorption efficiency was over 95% (100 mg L-1). The results were fitted with three kinetic and three equilibrium theoretical adsorption models. The adsorption process has good correlation with pseudo-second-order reaction kinetics. Adsorption mechanism was found to be controlled by pore, film and particle diffusion, throughout the entire adsorption period. The monolayer adsorption capacities were found to be 179.476, 105.844 and 78.798mg g(-1) for Pb2+, Cd2+ and Ni2+, respectively. Thermodynamic parameters such as Gibbs energy, enthalpy and entropy were also calculated. Additionally, preliminary results indicated a strong affinity of the biochar for selected organic micropollutants: naproxen and chlorophenols. Based on desorption study results, biochar was successfully regenerated in 3 cycles with diluted phosphoric acid produced as a waste stream during washing of the biochar after thermochemical activation. The experimental results were applied in a two-stage completely stirred tank reactor design. Cost estimation of AsPhA production substantiated its cost effectiveness and adsorption costs of selected pollutants were 5 times lower than with the commercial activated carbons. Based on the low-cost and high capacity, engineered biochar can be used as a highly efficient eco-friendly adsorbent for removal of heavy metal and organic micropollutants from wastewaters systems

    Utilization of fruit processing industry waste as green activated carbon for the treatment of heavy metals and chlorophenols contaminated water

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    Plum stones, as a part of industrial and municipal organic waste, were used as a precursor for preparation of a low-cost activated carbon. Engineered, thermochemically-modified adsorbent was used to remove lead (Pb2+), cadmium (Cd2+), nickel (Ni2+) and chlorophenols from an aqueous solution. The characterization of the medium was performed using standard instrumental analysis. Additionally, the assessment included the influence of pH, adsorbent dosage, temperature, contact time and initial metal concentration on the separation efficiency in the batch-operational mode. With optimal working conditions, the process efficiency of over 95% was accomplished. The equilibrium and kinetic studies of adsorption were done. The pseudo-second order model described the adsorption kinetics best. The maximum adsorption capacity of the engineered adsorbent for Pb2+, Cd2+ and Ni2+ ions was calculated from the Langmuir isotherms and found to be 172.43 mg g(-1), 112.74 mg g(-1) and 63.74 mg g(-1), respectively. Preliminary results indicate a strong affinity of the separation medium for chlorophenols. Thermodynamic parameters such as Gibbs energy, enthalpy and entropy were calculated. Regeneration of the saturated adsorbent was conducted, with diluted phosphoric acid produced as a waste stream, during the washing of the adsorbent after activation. Based on the desorption study results, the activated carbon was successfully regenerated in 3 cycles. Mutual influence of ions was analyzed in multicomponent systems. The real system production and operational costs analysis confirmed a possibility for a successful implementation of the highly efficient, eco-friendly engineered adsorbent in the field of cost-effective wastewater treatment.The peer-reviewed version: [http://cer.ihtm.bg.ac.rs/handle/123456789/2942

    Evaluation of the adsorption potential of eco-friendly activated carbon prepared from cherry kernels for the removal of Pb2+, Cd2+ and Ni2+ from aqueous wastes

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    Development, characterization and evaluation of the efficiency of cost-effective medium for the removal of Pb2+, Cd2+ and Ni2+ from aqueous systems, as a novel, eco-friendly solution for wastewater remediation were done. The precursors for low-cost adsorbent were lignoceilulosic raw materials (sweet/sour cherry kernels), as industrial byproducts and components of organic solid waste. Activated carbon synthesis was carried out by thermochemical conversion (H3PO4, 500 degrees C) in the complete absence of inert atmosphere. Characterization of the activated carbon was performed by elemental analysis, FTIR, SEM, EDX and BET. BET surface area corresponds to 657.1 m(2) g(-1). The evaluation also included the influence of pH, contact time, solute concentration and adsorbent dose on the separation efficiency in the batch operational mode. The equilibrium and kinetic studies of adsorption were done. The maximum adsorption capacity of the activated carbon for Cd2+ ions was calculated from the Langmuir isotherm and found to be 198.7 mg g(-1). Adsorption of Pb2+ and Ni2+ were better suitable to Freundlich model with the maximum adsorption capacity of 180.3 mg g(-1) and 76.27 mg g(-1), respectively. The results indicate that the pseudo-second-order model best describes adsorption kinetic data. Based on desorption study results, activated carbon was successfully regenerated with HNO3 for 3 cycles. In order to provide the results for basic cost-effective analysis, competing ion-effects in a real sample have been evaluated. (C) 2016 Elsevier Ltd. All rights reserved.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3508
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